Relearn and Retake: Genetics Quiz

If you have siblings (or know someone who has siblings) you may have noticed that you look both similar to and different from each other (even if you came from the same set of parents). Which of Mendel's Laws explains this phenomena?

Free earlobes hang below the point where the ear lobe attaches to the head. Attached earlobes do not hang, but are attached to the head. The gene for free earlobes is dominant (F), while the gene for attached earlobes is recessive (f). Both of Ashley’s parents have free earlobes but also carry a recessive gene for attached earlobes. Ashley has attached earlobes, so she must have a genotype of

Consider the genetic cross for absent-mindedness, which is a dominant trait. What is the probability (percentage) that the offspring of this cross will be absent minded (AA or Aa)